Die



Nov. 7, 1939. M051- 2,178,803

DIE

Filed March 18, 1939 INVENTOR 1-1.7. flint BY W 4 ATTORNEY Patented Nov. 7, 1939 UNITED STATES PATENT orrics Y 4 Claims.

My invention relates to a die forming part of the feeding means in a mechanical pencil of the type described in my pending application, Serial No. 209,739, filed May 19, 1933.

The object of the invention is to provide a die which would insure the engagement thereof with the lead it is to feed in a mechanical pencil.

In the appended drawing, forming part of 10 this application, Figure 1 is a top view of a die intended for a lead of a triangular crosssection.

Figure 2 is a section on line 22, Figure 1. Figure 3 is a top view of a die intended for a 15 lead, square in cross-section, and

Figure 4 is a top view of a die for a lead, rectangular in cross-section.

Referring to Figures 1 and 2 of the drawing, the die 5 has a threaded bore 6, which at one 20 end has notches or grooves 7 extending through a fraction of the said bores length. These notches I are of a depth slightly exceeding that of the threads in the bore. The notches are preferably formed by broaching the bore of 25 the die through a fraction of its length, and it may be generally said that the length of these notches exceeds the depth thereof materially when formed in the threaded bore at one end of the die.

The purpose of these grooves or notches in the bore is to permit a lead ofangular crosssection, in this particular case a triangular cross-section, to enter said notches when the die is turned relatively to the lead. The angles 5 of the triangular lead entering the notches insure a positive engagement between the threads of the die and the lead, when the die is turned relatively to the lead.

Where the die is intended for a lead of square 40 cross-section, there will be four notches l, as shown in Figure 3, the notches in this case being an equi-distance from each other as in the previous case as indicated in Figure 1.

Where the lead is of rectangular shape, the

notches 1" will be formed as indicated in Figure. 4.

It is self-evident that the die intended for a prismatic lead of polygonal cross-sections will have in the threaded bore as many notches or 5 grooves as there are angles in the cross-section of the lead it is to engage.

The notches in the bore at one end thereof each form the edge of a prism, and correspond in number to the number of edges of the lead 10 the die is designed to engage.

I claim:

1. A die of the class described, having a threaded bore prismatically notched at one end through the depth of the threads, and extendin through a fraction of the bores length. r

2. A die of the class described, having a threaded bore provided with a plurality of notches located at one end of the bore and forming a prismatic recess in the bore to engage a corresponding prism, the notches being substantially the depth of the thread in the bore, and the length of the notch in its bore exceeds the depth.

3. A die of the class described, having a threaded bore provided with a plurality of notches located at one end of the bore, the depth of notches being substantially the depth of the thread in the bore, and its length in said bore being a fraction of the bores length, said notches forming the angles of a prismatic recess.

'4. A die for mechanical pencil for direct engagement with a lead of angular cross-section comprising a threaded bore, provided with three notches at one end thereof. each of said notches being substantially in depth the depth of the thread in the bore, the length or depth of each of said notches from the end in which they are formed, is only a fraction of the bores length or depth, said three notches in the die consti- 40 tuting the edges of a triangular prism of equilateral cross-section.

LUCIFER J. MOST. 

